Racks for carrying bikes on motor vehicles often use hangers, clamps, straps, or cams to hold the bike in the rack. These require multiple operations to secure or release the bike. Hangers and clamps can mar the finish of a bike assembly during vibration of a traveling vehicle. Straps are subject to loosening, tearing, and deterioration.
Bike wheels should not be free to spin in the slipstream of a motor vehicle, and the steering wheel of the bike should not be free to turn. Otherwise, damage to the bike and/or the motor vehicle can result. Many racks do not inherently secure the wheels, relying on the competence and discretion of the user to do so with straps.
U.S. Pat. No. 4,875,608 (Graber) shows a folding bike carrier mounted on the rear of a vehicle. Each wheel is strapped to a tray, and the bike assembly is clamped to the carrier. This design secures the wheels, but the straps and clamps have the disadvantages described above.
U.S. Pat. No. 3,659,762 (Kravitz) shows a bike carrier with deep wells for holding a bike by its wheels. The bike must be strapped to the wells, since it is not clamped by them. Otherwise the bike could fly upward during a bump in the road. There is no adjustment for different sized bikes, so the wells are a loose fit, requiring straps to eliminate play of the bike within the wells.
Some bike carriers require removal of the front wheel, and bolting or clamping of the front dropouts to the carrier. This is inconvenient, even with a quick-release hub on the bike and/or a quick-release dropout clamp on the carrier. The front wheel must be strapped individually to the carrier or stowed elsewhere, possibly bending the rim or spokes, or scratching the carrier or vehicle.
The present inventor has commercial success with a bike carrier described in part in U.S. Pat. No. 5,833,074, filed May 6, 1995. Since this patent issued the inventor has improved the design, added a trailer hitch receiver embodiment, and has sold vehicle roof rack and hitch receiver versions. The carrier described herein incorporates aspects from the above patent '074, intervening improvements that were on sale over a year before the priority date (Jan. 2, 2017), and further improvements not publicly disclosed as of the priority date. Intervening improvements applicable to both the roof rack and the hitch receiver versions include the following:                a) Wheel retention arms with two parallel side arms and a cross member, which, in combination, form an H-shape or inverted U-shape depending on the position of the cross member, which can be adjusted for different sized bike tires. Adjustment requires a wrench and is limited to a selection of alternate bolt holes on the parallel side arms. It is not infinitely adjustable.        b) The pivotal position of each wheel retention arm is controlled by a linear ratchet with shallow, symmetric ratchet teeth. The pawl can be over-rotated by the user in the release direction, causing drag on the pawl movement while opening the wheel retention arms.        
A trailer hitch receiver version of the bike carrier with the following features were on sale for over a year before the priority date.                a) A main tray assembly with two aligned bicycle wheel trays to receive the front and back wheels of a bike. The main tray assembly is pivotally attached to a trailer hitch drawbar, allowing the assembly to pivot upward into a compact position behind a motor vehicle. The user must reach under the main tray assembly to reach the pivot release bar.        b) The two wheel trays pivot into a parallel position over the drawbar for compact shipping and storage without disassembly. The trays lock in the deployed position by respective levers, but the user must remember this. They do not automatically lock.        c) An add-on tray assembly can be bolted to the main tray assembly to carry a second bike or up to three bikes using two add-on assemblies. The user must reach under all tray assemblies to reach the tray assembly pivot release bar.        
The present inventor also invented a quick-release drawbar mechanism as disclosed in U.S. Pat. No. 6,406,051 for use on his bike carrier. He later devised and sold a drawbar with a screw-operated internal rod that pushes a captive ball to extend from a side of the drawbar to lock it in the tubular hitch receiver.
Since the priority date of Jan. 2, 2017, the inventor has made further improvements disclosed herein.